A conventional screwdriver having a lamp received therein is disclosed in U.S. Pat. No. 5,772,308 to Lin, which is issued on Jun. 30, 1998 and has the title of "Lamp Circuit Assembly Of A Screwdriver". In the screwdrivers disclosed and mentioned in the referenced patent of U.S. Pat. No. 5,772,308, as shown in FIG. 5, two lamps 220 are connected to the conductive plate 222 by two respective lines 221, and the assembly of the conductive plate 222 and the lamps 220 are then riveted to the positioning board 24 so that when the assembly is received in the handle 10 of the tool, the conductive plate 222 is located at the position to properly contact the batteries 200. The manufacturers have to prepare machines to proceed the riveting process of the conductive plate 222 and the positioning board 24 so that a higher manufacturing cost is incurred. Furthermore, the cap 26, the button assembly 25, the batteries 200, the assembly of the lights 200 and the positioning board 24 are separated with each other so that the users or the assemblers will take time to receive them in or remove them from the handle 10. During the removing and receiving actions, some of the parts could drop and the contact between the batteries 200 and the conductive plate 222 could change because the deformation of the conductive plate 222 or other unexpected situations.
The present invention intends to provide a screwdriver having a cassette which is securely and removably received in the handle of the tool and the batteries, the assembly of the lights are well positioned in the cassette so that it is convenient for the users or the manufacturers to insert the cassette or remove the cassette from the handle of the tool. The conductive plate is attached to the inside of the cassette so that the batteries can easily contact the conductive plate in the cassette.